In context of Golden Signals in Instana monitoring, what is the true definition of latency?

Latency is one of the four principal Golden Signals monitored in Instana and critical for measuring system performance and user experience. According to IBM Instana Observability documentation: "Latency is the time it takes to handle or service a request, measured as the duration between request start and response end." This applies regardless of protocol (HTTP, RPC, messaging, etc.) and is used to evaluate whether services are fast or slow under real load. Instana automatically tracks latency for every transaction, as shown in traces and metrics: this enables teams to identify slow services, resource contention, and downstream delays. Golden Signals (latency, error rate, traffic, saturation) provide a universal framework recognized in both SRE and performance engineering disciplines. The actual duration a user spends logging in or opening a webpage may be an instance of latency, but Instana’s definition is generalized to any service request (API, DB, etc.), not just interactive browser events. Error count is monitored separately (error signal).